1. Field of the Invention
This invention relates to polyfunctional aziridines for use in crosslinking applications which are the reaction products of ethylene imine and acrylates of alkoxylated trimethyol propane, neopentyl glycol, pentaerythritol, bis phenol A, bis phenol F and glycerol.
2. Description of the Prior Art
Polyfunctional aziridines have been shown to be useful as crosslinking agents in various types of coating systems such as carboxylated acrylics, vinyl-acetate, carboxylated urethanes and styrene acrylics. Commercially available polyfunctional aziridines are trifunctional in character and are reaction products of ethylene imine or propylene imine with trimethylol propane triacrylate and ethylene imine with pentaerythritol triacrylate. They are effective low temperature crosslinking agents when added to a coat system in amounts of 0.2 to 5.0% by weight of total formula.
The choice of crosslinking agent used in a coating system has a significant effect on the preparation of the coating system as well as on the overall properties of the cured coating. Factors such as water solvency, viscosity, and functionality will have a bearing on the ease of preparing the coating.
Regarding the previously mentioned polyfunctional aziridines which are used commercially, these materials are effective crosslinking agents but tend to be low in water solubility, have negative features in toxicity and are poor in corrosion, adhesion and humidity resistance.
The above and other polyfunctional aziridines are, for example, described in the following patents:
U.S. Pat. No. 2,596,200--Bestian--May 13, 1952 PA1 U.S. Pat. No. 3,165,375--Tesoro--Jan. 12, 1965 PA1 U.S. Pat. No. 3,197,463--Tesoro et al--July 27, 1965 PA1 U.S. Pat. No. 3,285,798--Tesoro--Nov. 15, 1966 PA1 U.S. Pat. No. 3,338,885--Coker et al--Aug. 29, 1967 PA1 U.S. Pat. No. 3,597,146--Tesoro--Aug. 3, 1971 PA1 U.S. Pat. No. 3,726,862--Coker et al--Apr. 10, 1973
Aqueous coating compositions containing aziridine crosslinking agents are described in U.S. Pat. No. 4,278,578--Carpenter, July 14, 1981.